Topsolar 20 Watt 18 Volt Solar Trickle Charger 20 Watt 18 Volt Solar Panel Car Battery Charger Portable Solar Battery Maintainer for Cars, Motorcycles, Boats, Ships, RVs, Trailers, Snowmobiles, etc

Works to keep a battery topped up
I originally bought this panel with the idea of putting it on my shed roof and using it to keep my lawn tractor battery topped up. My tractor is old and the charging system is pretty much non-existent, but since the battery is mostly used only to crank the engine, I can get through an entire season with it.Almost.The battery, like the tractor, is starting to get a little tired. I’ve found myself having to take it out and charge it to get through this season. Let’s face it, this battery is on its last legs, and I’m just hoping I can get through the next few weeks with it.So I bought this solar panel and immediately ran out of time to install it on the tractor. Instead, I stuck it in my truck. My poor old truck sits unused for weeks at a time. It always starts, but it tends to crank pretty slowly because the battery draws down between uses. This charge/discharge cycle is hard on both batteries and alternators, and both have gotten too expensive to abuse and potentially damage.Since I don’t drive the truck much and I don’t want to run a battery tender outside, I decided to repurpose the solar panel as a truck battery maintainer. For this, it works perfectly.The panel mounts to the inside of the windshield with four suction cups. Easy to put on, easy to remove when I want to drive. The panel itself is very thin so I have to treat it gingerly. I wish I could find a solution that didn’t involve removing it every time I want to use the truck but so far I haven’t. We’ll see how it holds up over time to being repeatedly installed or removed. I envision flexing it just a little too much and hearing a fatal cracking sound but so far it’s been fine.The panel uses SAE connectors which allows you to attach to the cigarette lighter dongle, alligator clips, or dedicated ring terminals. I use the cigarette lighter adapter because the lighter socket is live on my truck all the time. If your vehicle disconnects the lighter socket when the ignition is turned off, you’ll have to figure something else out.SAE connectors are hermaphroditic connectors. That means that two SAE connectors will plug together, but the polarity will reverse (IE the “positive” terminal of one will feed the “negative” terminal of the next one). I triple-checked that the panel would not be wired in reverse polarity in my installation. The panel has a reverse-polarity indicator but I prefer to use a multimeter and see for myself. You can get polarity reversing adapters if you need them but I didn’t.Last time I went to use my truck, the panel had been on and charging for about a week. The truck cranked just as quickly as if I’d put the battery on a dedicated charger. I haven’t checked current output or state of charge of the battery, but my seat-of-the-pants analysis tells me that it’s keeping the battery topped up. Impressive considering we’ve had a few cloudy/rainy days this week. We’ll see how well it works over the winter.In all I’m impressed with this panel. It’s a simple solution that (so far) seem to work well. It’s WAY less expensive than buying a battery so if it continues to work, I will consider it money well spent. I’ll update once I’ve used it a while longer.

Good product for sure 😃
It works good for what it was made for heavy duty made cuz i dropped it a few times on cement and not a scratch on it and still performing as good as day one

Cheap and it works!
Limited use vehicle, battery was not holding a charge. Plugged this in to a “hot” outlet. No more issues with dead battery.

Appears to be a high quality product. Built in charge regulator is a big bonus.
I won’t be able to hook this up to my boat battery until later this summer but my first impression of this charger is that it is a well-designed and well-built product. I appreciate the fact that it includes ring-type connectors for the threaded battery posts found on marine batteries rather than having to use alligator clips which tend to pop off with the slightest jostling (alligator clips are also included though).When placed in a double pane house window on an overcast June day in Alaska, I measured a no load13.7 volts output which promises to perform well whenb maintaining a lead-acid battery. I assume that voltage is indicative of a well-functioning voltage controller in this unit because at the time the solar array on my roof was only showing 40% capacity.Based upon the apparent build quality and appropriate voltage measurement, I’m giving it a provisional 5 stars which I will revisit if it becomes necessary after I see how it holds up under use in a salty environment.